Tubulation tubing of display panel

ABSTRACT

Tubulation tubing of a display panel includes a flange at one end and a ring-shape adhesive member placed on a display panel to align a vent hole of the display with an opening of the tubulation tubing and the flange of the tubulation tubing is bonded to the display panel via the adhesive member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Ser. No. 10/447,943 filed May30, 2003 and entitled “TUBULATION TUBING OF DISPLAY PANEL,” now U.S.Pat. No. 6,998,161, which was a divisional of U.S. Ser. No. 09/717,130,filed Nov. 22, 2000, and entitled “METHOD OF BONDING TUBULATION TUBINGAND DISPLAY PANEL,” now U.S. Pat. No. 6,591,635.

This application is related to Japanese Patent Application No.2000-123268 filed on Apr. 24, 2000, whose priority is claimed under 35USC §119, the disclosure of which is incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of bonding a tubulation tubingof a display panel, more particularly, a method of bonding a tubulationtubing to a display panel such as a plasma display panel (PDP) forremoving an impurity gas from an electric discharge space in the displaypanel and introducing an electric discharge gas into the dischargespace.

2. Description of Related Art

In a display panel such as a PDP, the discharge space is usually formedin the panel by disposing a front substrate and a back substrate of thepanel opposedly and sealing the peripheries of the substrates together.Typically, in the production of the panel, a vent hole is opened in theback substrate and a glass tubulation tubing is bonded to the perimeterof the vent hole when the front and back substrates are sealed together.Via this tubulation tubing, the impurity gas is removed from the insideof the panel and the discharge gas is fed in the panel. Thereafter, thetubulation tubing is cut by fusing (melting) so that a tubulation pathin the tubulation tubing is closed, thereby making the discharge spaceair-tight.

In order to bond the tubulation tubing to the back substrate, usually, aglass frit or glass powder is mixed with a binder and formed in a ringshape. This glass material (also referred to as a sealing glass) ispreliminarily baked to release gas therefrom and placed between a flareedge of the tubulation tubing and the back substrate. The glass materialis fastened provisionally with the tubulation tubing by means of a clip.Thereafter a sealing step is conducted for sealing the front substrateand the back substrate together (by fusing a sealing member with heat),thereby also welding the tubulation tubing to the back substrate withthe glass material.

However, since the glass material is between the flare end portion ofthe tubulation tubing and the back substrate, the glass material,melted, may enter the inside of the tubulation tubing and block thetubulation tubing when the tubulation tubing and the back substrate arebonded by melting the glass material. The melted glass material may alsoenter the inside of the panel when the impurity gas is vented out andthe discharge gas is fed into the panel.

Where the sealing step is carried out after the glass material has beenprovisionally fastened together with the tubulation tubing by a clip,the glass material softened in the sealing step is pushed out frombetween the flare end portion of the tubulation tubing and the backsubstrate and adheres to the clip. As a result, it may become difficultto remove the glass material when the clip is taken off or the glassmaterial may crack when removed.

Further, if the pressing force by the clip for holding the tubulationtubing is too strong, the glass member is pushed out from the flare endportion of the tubulation tubing. For this reason, the pressing forcecannot be strengthened above a certain degree. Therefore, when thesealing step is carried out with the glass material being provisionallyfastened together with the tubulation tubing by the clip, the tubulationtubing may possibly be inclined when a little force is applied.

SUMMARY OF THE INVENTION

In these circumstances, the present invention is intended to provide amethod of bonding a tubulation tubing of a display panel which canprevent the entry of the adhesive member into the tubulation tubing orthe adhesion of the adhesive member to the clip, by preparing atubulation tubing having a flange with a substantially flat end face andan adhesive member to be fitted to the perimeter of the flange of thetubulation tubing, placing the tubulation tubing and the adhesive memberat a vent hole of a display panel, and pressing the flange against thedisplay panel with a clip to bond the tubulation tubing to the displaypanel.

The present invention provides a method of bonding a tubulation tubingof a display panel comprising the steps of: preparing a tubulartubulation tubing having, at one end, a flange with a substantially flatend face and a ring-shape adhesive member to be fitted to the perimeterof the flange of the tubulation tubing; placing the tubulation tubingand the adhesive member on a display panel having a vent hole in such amanner that the end face of the flange of the tubulation tubing contactsthe display panel and the vent hole is covered with an opening of thetubulation tubing; and holding the tubulation tubing by pressing theflange of the tubulation tubing to a face of the display panel with useof a pressing tool and heating to a temperature at which the adhesivemember softens, thereby bonding the flange of the tubulation tubing tothe display panel by fusion of the adhesive member.

According to the present invention, the tubulation tubing having, at oneend, the flange with a substantially flat end face and the ring-shapeadhesive member to be fitted to the perimeter of the flange of thetubulation tubing are prepared. The tubulation tubing and the adhesivemember are placed on the display panel, and the tubulation tubing isheld by pressing the flange of the tubulation tubing against the displaypanel face with a pressing tool. Therefore, the pressing tool does notcontact the adhesive member directly, which prevents the adhesive membersuch as glass from adhering to the pressing tool, for example, a clip.

Further, the tubulation tubing having the adhesive member already fittedto the periphery of the flange is placed on the display panel with theend face of the flange of the tubulation tubing contacting the displaypanel, and the tubulation tubing is held by pressing the flange of thetubulation tubing against the display panel face with the pressing tool.Therefore, the melted adhesive member does not enter the inside of thetubulation tubing. Also, since the pressing force of the clip can bestrengthened, the inclination of the tubulation tubing by external forcecan be suppressed.

These objects of the present application will become more readilyapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates Example 1 of the method for bonding a tubulationtubing of a display panel in accordance with the present invention;

FIG. 2 illustrates a state in which a tubulation assembly is placed atthe position of a vent hole on a back substrate in the production of adisplay panel in accordance with Example 1;

FIG. 3 is a plan view illustrating a state in which the tubulationtubing and the display panel are clamped by a clip in Example 1;

FIG. 4 is a sectional view illustrating the vicinity of a flange of thetubulation tubing before a sealing step in Example 1;

FIG. 5 is a sectional view illustrating the vicinity of the flange ofthe tubulation tubing after the sealing step in Example 1;

FIGS. 6( a) to 6(c) illustrate Example 2 of the method for bonding atubulation tubing of a display panel in accordance with the presentinvention;

FIG. 7 illustrates a state in which a tubulation assembly is placed atthe position of a vent hole on a back substrate in the production of adisplay panel in accordance with Example 2;

FIG. 8 is a sectional view illustrating the vicinity of a flange of thetubulation tubing before a sealing step in Example 2;

FIG. 9 is a sectional view illustrating the vicinity of the flange ofthe tubulation tubing after the sealing step in Example 2;

FIG. 10 is a flowchart showing sealing and gas venting processes in theExamples;

FIG. 11 illustrates an example according to Example 2 in which anauxiliary pressure member reduces the etching of an adhesive member byan acid to a minimum in Example 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The method of bonding a tubulation tubing to a display panel of thepresent invention can be applied to any kind of panel that has a spaceinside the panel and requires the removal of a gas from the space and/orthe introduction of a gas into the space via a vent hole provided to thepanel. As examples of such display panels, PDPs, plasma address liquidcrystal (PALC) panels, VFD (Vacuum Fluorescence Display) and FED (Fieldemission Display) may be mentioned.

In the present invention, a tubular glass pipe known in the field of artmay be used as the tubulation tubing. The tubulation tubing is typicallya cylindrical pipe. However, it suffices that the tubulation tubing canpass air/gas through, and accordingly the shape of the tubulation tubingdoes not necessarily need to be cylindrical. As an example of glassmaterial for the tubulation tubing, soda lime glass (typically having asoftening point of 500 to 700° C.) may be mentioned. At the opening atthe one end of the tubulation tubing, the flange having a substantiallyflat face is formed. The flange can be produced by a known method. Sincethe end face of the flange is a face contacting the substrate, it ispreferably formed as flat as possible for preventing gas leakage and thelike from this contact face.

The adhesive member is a member for bonding the one end of thetubulation tubing to the display panel. The adhesive member may beformed of any material that has a lower softening point than thesoftening point of the tubulation tubing. Generally, the tubulationtubing is bonded simultaneously when the front and back substrates ofthe display panel are sealed together. In this sealing step, the displaypanel is placed in an oven and the temperature in the oven is raised tothe softening point of a sealing member provided in the periphery of thesubstrates. This sealing temperature varies depending on the type of thesealing member, but since a low softening point glass is usually used asthe sealing member, the sealing temperature is about 400 to 410° C.

Therefore, the adhesive member is preferably formed of a glass materialhaving a softening point of 400° C. or lower, preferably a softeningpoint of 390 to 400° C. for preventing over-melting of the adhesivemember. As an example of such material, a low softening point glasscontaining PbO—B₂O₃ may be mentioned.

For example, as a material for the adhesive member, a low softeningpoint glass frit containing PbO, SiO₂, Al₂O₃, B₂O₃ and LiO which has asoftening point of about 390□ and a thermal expansion coefficient of72.5±5×10⁻⁷/° C. may be used, and a binder resin known in the field suchas acrylic resin, methacrylic resin, cellulose resin or the like may beadded to the low softening point glass frit. This material may bepress-molded in a doughnut shape having a substantially rectangularsection, and then baked.

In addition to the above-mentioned example, the adhesive member may be acompression-molded glass member of the above-mentioned low softeningpoint glass frit or a molded glass paste member of the above lowsoftening point glass frit blended with the binder resin which is notbaked. Even if the molded glass paste, without being baked, isprovisionally fixed to the perimeter of the flange of the tubulationtubing and the flange of the tubulation tubing is bonded to the displaypanel in the sealing step, the molded glass paste is bakedsimultaneously in the sealing environment. At this time, if gas isgenerated by the combustion of the binder resin in the case where themolded glass paste member is used, the generated gas does not enter thetubulation tubing from an abutment of the tubulation tubing and thedisplay panel.

The provisional fixation of the adhesive member to the tubulation tubingmay be carried out by attaching the adhesive member to the flange of thetubulation tubing and then heating them in an oven at about 380 to 390°C., at which the adhesive member softens, for 10 to 30 minutes, therebybonding by fusing the adhesive member to the flange of the tubulationtubing. It is preferable to produce a number of tubulation tubings withthe adhesive members bonded thereto beforehand by a process separatefrom the process of assembling display panels.

The auxiliary pressure member is an auxiliary member for pressing theadhesive member and the flange of the tubulation tubing attached to theadhesive member toward the display panel. The auxiliary pressure membermay be formed of any kind of material that has a higher softening pointthan that of the adhesive member and has a thermal expansion coefficientsubstantially the same as that of the adhesive member for preventingcracks. However, since the tubulation tubing is typically bondedsimultaneously when the display panel is sealed, the auxiliary pressuremember preferably has a softening point not lower than the sealingtemperature.

Preferably, the auxiliary pressure member has a non-oxidizable property.If the tubulation tubing is bonded in the sealing step, a protectivelayer for a terminal section of the display panel is removed after thesealing step. In this removal step, the terminal section of the displaypanel is immersed in nitric acid for removing an anti-oxidant paste inthe terminal section. For protecting the adhesive member in the removalstep, the auxiliary pressure member preferably has the non-oxidizableproperty.

Accordingly, the auxiliary pressure member is preferably formed of aglass material having a softening point not lower than 500° C. As anexample of such material, a lower softening point glass containingNa₂O—B₂O₃ may be mentioned. In addition, ceramics and the like may beused.

For example, as a material for the auxiliary pressure member, a lowsoftening point glass frit containing Na₂O, Al₂O₃, B₂O₃ and SiO₂ whichhas a softening point of 500° C. or higher and a thermal expansioncoefficient of 72.5±5×10⁻⁷/° C., which is the same as that of theadhesive member, may be used, and a binder resin known in the field suchas acrylic resin, methacrylic resin, cellulose resin and the like may beadded to the low softening point glass frit. This material may bepress-molded in a doughnut shape having a substantially rectangularsection, and then baked. Preferably, the auxiliary pressure member isbaked.

The provisional fixation of the auxiliary pressure member and theadhesive member to the tubulation tubing may be carried out by attachingthe tubulation tubing to a jig with the flange positioned on the top,sequentially mounting the auxiliary pressure member and the adhesivemember on the flange of the tubulation tubing, and then heating them inan oven at about 380 to 390° C., at which the adhesive member softens,for 10 to 30 minutes, thereby bonding by fusing the adhesive member tothe flange of the tubulation tubing and the auxiliary pressure member.

The thus prepared tubulation tubing is placed on the display panelhaving a vent hole so that the end face of the flange of the tubulationtubing is contacted with the display panel and the vent hole is coveredwith the opening of the tubulation tubing. At this time, since the endface of the flange is substantially flat, it is easy to contact and holdit to the display panel.

Thereafter, the tubulation tubing is held by pressing the flange of thetubulation tubing or the auxiliary pressure member toward the displaypanel face by means of the pressing tool. Then the flange of thetubulation tubing is bonded to the display panel by fusion of theadhesive member by heating to the temperature at which the adhesivemember softens. Any kind of tool can be used as the pressing tool, but aclip is typically used.

The temperature at which the adhesive member softens is 390 to 400° C.as described above. However, in the case where the tubulation tubing isbonded simultaneously with the sealing step, the temperature may beraised to about 400 to 410° C. In this case, heating to the softeningtemperature or higher does not cause troubles, because the adhesivemember has a high viscosity.

Desirably, the thickness of the auxiliary pressure member is smallerthan that of the flange in a longitudinal direction of the tubulationtubing. Also desirably, the total thickness of the adhesive member andthe auxiliary pressure member is larger than that of the flange in thelongitudinal direction of the tubulation tubing. With this setting ofthe thickness of the adhesive member and the auxiliary pressure member,the flange of the tubulation tubing stops the movement of the auxiliarypressure member, for example, by a clip, in a pressing direction whenheated at the temperature at which the adhesive member softens. This canprevent excessive pressure on the adhesive member.

The present invention also provides a method of bonding a tubulationtubing of a display panel comprising the steps of: preparing a tubulartubulation tubing, a ring-shape adhesive member and a ring-shapeauxiliary pressure member which are to be fitted to the perimeter of oneend of the tubulation tubing, the ring-shape auxiliary pressure memberhaving a higher softening point than that of the adhesive member;placing the tubulation tubing on a display panel having a vent hole insuch a manner that said one end of the tubulation tubing contacts thedisplay panel and the vent hole is covered with an opening of thetubulation tubing, with the adhesive member and the auxiliary pressuremember being fitted to the tubulation tubing so that the adhesive memberis situated on a display panel side; and holding the tubulation tubingby pressing the auxiliary pressure member toward the display panel withuse of a pressing tool and heating to a temperature at which only theadhesive member softens, thereby bonding an end face at said one end ofthe tubulation tubing to the display panel by fusion of the adhesivemember.

According to the present invention, prepared are the ring-shape adhesivemember and the auxiliary pressure member having a higher softening pointthan the adhesive member, which are fitted to the perimeter of one endof the tubulation tubing. The adhesive member and the auxiliary pressuremember are fitted to the tubulation tubing so that the adhesive memberis located on a display panel side. The tubulation tubing is held bypressing the auxiliary pressure member toward the display panel with useof the pressing tool. Therefore, the pressing tool does not contact theadhesive member directly, which prevents the adhesive member such asglass from adhering to the pressing tool, for example, a clip.

Further, the tubulation tubing is placed on the display panel with oneend of the tubulation tubing contacted with the display panel and alsothe adhesive member and the auxiliary pressure member are fitted to theperimeter of said one end of the tubulation tubing. The tubulationtubing is held by pressing the auxiliary pressure member toward thedisplay panel with use of the pressing tool. Therefore, the meltedadhesive member does not enter the inside of the tubulation tubing.Also, since the pressing force by the clip can be strengthened, theinclination of the tubulation tubing by external force can besuppressed.

The present invention also relates to a tubulation adhesion structure inwhich a flange of a tubulation tubing is bonded to a display panel bythe above-described method.

The present invention further provides a tubulation assembly to beconnected to a vent hole of a display panel for venting gas out of theinside of the panel. The tubulation assembly includes a hollowtubulation tubing having, at one end, an opening for communicating withthe vent hole of the display panel and a flange with a substantiallyflat end face for contact with the display panel; a ring-shape adhesivemember of a glass frit integrally fitted to the perimeter of the flangeof the tubulation tubing; and a ring-shape auxiliary pressure memberintegrally fitted to the perimeter of the flange of the tubulationtubing so as to cover the adhesive member, the auxiliary pressure memberhaving a higher softening point than that of the adhesive member.

The present invention is now explained in further detail by way ofexamples with reference to the attached drawings. These examples,however, should not be construed to limit the scope of the invention.

EXAMPLE 1

FIGS. 1 to 5 illustrate Example 1 of the method of bonding a tubulationtubing of a display panel according to the present invention.

In this example, as shown in FIG. 1, a cylindrical tubulation tubing 1has a flange 2 with a substantially flat end face 2 a, at an opening atone end of the tubulation tubing (gas conduit tube) 1. A ring-shapeadhesive member 3 is provisionally bonded to the perimeter of the flange2 of the tubulation tubing 1. Thus a tubulation assembly 4 with theadhesive member is produced beforehand.

The tubulation tubing 1 is a cylindrical pipe made of a typical sodalime glass (having a softening point of 500 to 700° C.). The adhesivemember 3 is a molded glass member produced by blending a binder resinwith a low softening point glass frit, followed by molding and baking.

In this example, for the adhesive member 3, used is a low softeningpoint glass frit containing PbO, SiO₂, Al₂O₃, B₂O₃ and LiO and having asoftening point of about 390□ and a thermal expansion coefficient of72.5±5×10⁻⁷/° C., to which a binder resin known in the field of art suchas an acrylic resin, methacrylic resin, cellulose resin or the like isadded. This glass frit is press-molded into a doughnut shape having asubstantially rectangular section and attached to the flange 2 of thetubulation tubing 1, which is then placed in a heating oven and heatedat about 380 to 390□, at which the adhesive member 3 softens, for about10 to 30 minutes. Thus the adhesive member 3 is bonded to the flange 2of the tubulation tubing 1. Tubulation assemblies 4 are producedbeforehand in a large number by a process independent of the process ofassembling display panels.

Subsequently, as shown in FIG. 2, when the perimeter of a frontsubstrate 11 and a back substrate 12 is sealed with a sealing member 13containing a lower softening point glass as a main ingredient in theprocess of producing the display panel, the tubulation assembly 4 ispositioned at a vent hole 14 on the back substrate 12. At this time, thetubulation assembly 4 is so positioned that the end face 2 a of theflange 2 of the tubulation tubing 1 contacts the back substrate 12 andthe vent hole 14 is covered with the opening of the tubulation tubing 1.

After this positioning, the tubulation tubing 1 and the display panelare clamped with a clip 15 so that the tubulation tubing is held in sucha manner that the flange 2 of the tubulation tubing 1 is pressed againstthe display panel. At this pressing, the display panel is clamped atseveral sites on its periphery with similar clips.

FIG. 3 is a plan view illustrating a state in which the tubulationtubing 1 and the display panel are clamped with the clip 15. As shown inthis figure, the clip 15 is provided with a notch so that the flange 2of the tubulation tubing 1 can be pressed.

Next, while maintaining this state in which the tubulation tubing 1 andthe display panel are clamped with the clip 15, the sealing of thedisplay panel and the gas exhaustion of the display panel are carriedout. In these sealing and gas exhaustion steps, the display panel isplaced in a sealing and gas exhaustion oven. The display panel is bakedat a temperature of 400 to 410° C., at which the sealing member 13softens, to soften the sealing member 13 at the perimeter of the displaypanel and seal the front substrate 11 and the back substrate 12. Sincethe tubulation tubing 2, the front substrate 11 and the back substrate12 are made of soda lime glass, which has a softening point of about 500to 700° C., they are not softened at this baking temperature.

The adhesive member 3, heated in this step, softens, so that the flange2 of the tubulation tubing 1 is bonded to the back substrate 12 byfusion of the adhesive member 3.

In this state, where the front substrate 11 and the back substrate 12are sealed and the tubulation tubing 1 is also bonded to the backsubstrate 12, an impurity gas inside the panel is vented out via thetubulation tubing 1, and in turn the discharge gas is filled inside thepanel. Thereafter, the tubulation tubing 1 is cut by melting so that thegas path in the tubulation tubing 1 is closed, and thereby the dischargespace is shut tightly.

FIGS. 4 and 5 are sectional views illustrating the vicinity of theflange 2 of the tubulation tubing 1, FIG. 4 showing a state before thesealing step and FIG. 5 showing a state after the sealing step.

Before the sealing step, as shown in FIG. 4, the flange 2 of thetubulation tubing 1 is pressed by the clip 15, and after the sealingstep, as shown in FIG. 5, the flange 2 of the tubulation tubing 1 isbonded to the back substrate 12 by fusion of the softened adhesivemember 3. Accordingly, even if a small gap exists between the end face 2a of the flange 2 and the back substrate 12, the gap can be positivelyfilled up with the softened adhesive member 3.

Thus, in this example, the tubulation assembly 4 with the ring-shapeadhesive member 3 provisionally attached to the perimeter of the flange2 of the tubulation tubing 1 is produced beforehand. The tubulationtubing 1 is bonded to the display panel via the flange 2 using thetubulation assembly 4. Therefore, setting can be done by positioning thetubulation tubing 1 and the display panel alone, which facilitates theautomatization of production of display panels.

Also, since the tubulation tubing 1 is held by pressing the flange 2 ofthe tubulation tubing 1 against the display panel with the clip 15, theclip 15 does not contact the adhesive member 3 directly, which preventsthe adhesive member 3 from adhering to the clip 15.

Further, since the tubulation assembly 4 is located on the display panelwith the end face 2 a of the flange 2 of the tubulation tubing 1contacting the back substrate 12 and the tubulation tubing 1 is fixed bypressing the flange 2 of the tubulation tubing 1 against the displaypanel with the clip 15, the melted adhesive member 3 does not enter thetubulation tubing 1 even if the pressing force of the clip 15 isstrengthened. Therefore, it is possible to increase the pressing forceby the clip 15 and prevent the inclination of the tubulation tubing 1 byexternal force.

EXAMPLE 2

FIGS. 6( a) to 6(c) and FIGS. 7 to 9 illustrate Example 2 of the methodof bonding a tubulation tubing of a display panel according to thepresent invention.

First, as shown in FIGS. 6( a) to 6(c), used is a cylindrical tubulationtubing 1 having, at an opening at one end, a flange 2 with asubstantially flat end face 2 a. A ring-shape adhesive member 3 and aring-shape auxiliary pressure member 5 having a higher softening pointthan the adhesive member 3 are provisionally bonded to the perimeter ofthe flange 2 of the tubulation tubing 1 in this order from said one end.Thus a tubulation tubing assembly 7 with the members is producedbeforehand.

In this example, the adhesive member 3 is the same as that in Example 1.The auxiliary pressure member 5 is formed of a low softening point glassfrit containing Na₂O, Al₂O₃, B₂O₃ and SiO₂ and having a softening pointof about 500° C. and the same thermal expansion coefficient of72.5±5×10⁻⁷/° C. as that of the adhesive member 3, to which a binderresin known in the field of art such as an acrylic resin, methacrylicresin, cellulose resin or the like is added. This glass frit ispress-molded into a doughnut shape having a substantially rectangularsection.

The tubulation assembly 7 is produced by first setting the tubulationtubing 1 to a jig 6 with the flange 2 positioned on the top (see FIG. 6(a); subsequently setting the ring-shape auxiliary pressure member 5 onthe perimeter of the flange 2 by placing the member 5 on the jig 6; andthereafter setting the adhesive member 3 thereon (see FIG. 6( b)). Withthis state kept, the tubulation tubing 1 together with the members 3, 5and jig 6 is put in a heating oven and heated to soften the adhesivemember 3, so that the adhesive member 3 is bonded to the perimeter ofthe flange 2 and the auxiliary pressure member 5 is bonded to theadhesive member 3 (see FIG. 6( c)).

As shown in these figures, the thickness of the auxiliary pressuremember 5 is smaller than that of the flange 2 in the longitudinaldirection of the tubulation tubing 1. The total thickness of theadhesive member 3 and the auxiliary pressure member 5 is larger thanthat of the flange in the longitudinal direction of the tubulationtubing 1.

In the heating oven, heating is performed at about 380 to 390° C., atwhich the adhesive member 3 softens, for about 10 to 30 minutes as inExample 1. Thus, the adhesive member 3 is bonded by fusing to the flange2 of the tubulation tubing 1 and the auxiliary pressure member 5.Tubulation assemblies 7 are produced beforehand in a large number by aprocess independent of the process of producing the display panels.

Subsequently, as shown in FIG. 7 and as in Example 1, when the perimeterof a front substrate 11 and a back substrate 12 is sealed with a sealingmember 13 containing a lower softening point glass as a main ingredientin the process of producing the display panel, the tubulation assembly 7is positioned at a vent hole 14 on the back substrate 12. At this time,the tubulation assembly 4 is so positioned that the end face 2 a of theflange 2 of the tubulation tubing 1 contacts the back substrate 12 andthe vent hole 14 is covered with the opening of the tubulation tubing 1.

After this positioning, the auxiliary pressure member 5 and the displaypanel are clamped with a clip 15 so that the tubulation tubing is heldin such a manner that the adhesive member 3 and the flange 2 of thetubulation tubing 1 bonded to the adhesive member 3 are pressed towardthe display panel. At this pressing, the display panel is clamped atseveral sites on its periphery with similar clips. The clip 15 isprovided with a notch similar to that mentioned in Example 1, to allowthe auxiliary pressure member 5 to be pressed.

Next, while maintaining this state in which the auxiliary pressuremember 5 and the display panel are clamped with the clip 15, the sealingof the display panel and the gas exhaustion of the display panel arecarried out. These sealing and gas exhaustion steps are done at the sametemperature for the same period of time as described in Example 1.

The adhesive member 3, heated in this step, is softened, so that theflange 2 of the tubulation tubing 1 is bonded to the back substrate 12by fusion of the adhesive member 3. In this state kept, the impurity gasinside the panel is vented out, and in turn the discharge gas is filledinside the panel, via the tubulation tubing 1. Thereafter, thetubulation tubing 1 is cut by melting so that the gas path in thetubulation tubing 1 is blocked, and thereby the discharge space is shuttightly.

FIGS. 8 and 9 are sectional views illustrating the vicinity of theflange 2 of the tubulation tubing 1, FIG. 8 showing a state before thesealing step and FIG. 9 showing a state after the sealing step.

Before the sealing step, as shown in FIG. 8, the auxiliary pressuremember 5 is pressed by the clip 15, and after the sealing step, as shownin FIG. 9, the flange 2 of the tubulation tubing 1 is bonded to the backsubstrate 12 by fusion of the softened adhesive member 3.

As described above, the thickness of the auxiliary pressure member 5 issmaller than that of the flange 2 in the longitudinal direction of thetubulation tubing 1. The total thickness of the adhesive member 3 andthe auxiliary pressure member 5 is larger than that of the flange 2 inthe longitudinal direction of the tubulation tubing 1. Therefore, whenthe adhesive member 3 softens, the movement of the auxiliary pressuremember 5 by the clip 15 in the pressing direction is stopped by theflange 2 of the tubulation tubing 1, so that the adhesive member 3 isnot pressed.

After the inside of the panel is purged of the impurity gas and filledwith the discharge gas via the tubulation tubing 1, the protecting layerfor terminals is usually removed. Before the sealing and gas-exhaustionsteps, the surface of the terminals lead out in a peripheral region ofthe display panel has been coated with an anti-oxidation pastecontaining fine particles of zinc oxide for preventing the oxidizationof the terminals. At this step, this anti-oxidation paste on theterminals is removed.

The above-mentioned sealing and gas exhaustion steps are explained withreference to the flowchart shown in FIG. 10.

First, the front substrate 11 and the back substrate 12 areprovisionally fastened with a first clip in step S1; the tubulationtubing 1 is provisionally fastened with a second clip in step S2;subsequently, the display panel is placed in the sealing and gasexhaustion oven and a vacuum head is attached to the tubulation tubing 1in step S3; the sealing and gas exhaustion steps are conducted and thedischarge gas is fed in the panel in step S4; the tubulation tubing 1 ischipped off in step S5; the display panel is taken out of the sealingand gas exhaustion oven and the first and second clips are detached instep S6; and the protecting film for the terminals is removed in stepS7.

Thus, in this example, the tubulation assemblies 7 are producedbeforehand, in which the ring-shape adhesive member 3 and the auxiliarypressure member 5 are provisionally bonded to the perimeter of theflange 2 of the tubulation tubing 1. Since the flange 2 of thetubulation tubing 1 is bonded to the display panel using this tubulationassembly 7, the setting can be done only by positioning the twoelements, i.e., the tubulation tubing 1 and the display panel.Accordingly, the automatization is facilitated.

Also, since the tubulation tubing is fastened by pressing the auxiliarypressure member 5 toward the display panel with use of the clip 15, theclip 15 does not contact the adhesive member 3 directly and therefore,the adhesive member 3 is prevented from adhering to the clip 15.

Further, the tubulation assembly 7 is disposed with the end face 2 a ofthe flange 2 of the tubulation tubing 1 contacted with the backsubstrate, and the tubulation tubing 1 is held by pressing the auxiliarypressure member 5 toward the display panel with use of the clip 15.Therefore, even if the pressing force of the clip 15 is strengthened,the melted adhesive member 3 does not enter the inside of the tubulationtubing 1. The inclination of the tubulation tubing 1 owing to externalforce can be controlled by strengthening the pressing force of the clip15.

Besides, in the step of removing the protecting layer for the terminals,in which the anti-oxidation paste on the terminals is removed byimmersing the terminals of the display panel in nitric acid, theauxiliary pressure member 5 formed of the glass material which is acidresistant exists on the adhesive member 3. Therefore, the adhesivemember 3 underlies the auxiliary pressure member 5, and contacts nitricacid in only a small surface area, which can suppress the etching of theadhesive member 3 by the acid to a minimum.

According to the present invention, prepared are the tubulation tubinghaving, at one end, the flange with a substantially flat end face andthe ring-shape adhesive member to be attached to the periphery of theflange of the tubulation tubing. The tubulation tubing and the adhesivemember are placed on the display panel so that the vent hole of thedisplay panel communicates with the opening of the tubulation tubing.The flange of the tubulation tubing is pressed against the display panelface with use of the pressing tool, and the tubulation tubing is bondedby heating to a temperature at which the adhesive member softens.Accordingly, even if the adhesive member is formed of glass, forexample, the adhesive member can be prevented from entering thetubulation tubing and adhering to the clip.

1. A tubulation assembly to be connected to a vent hole of a displaypanel for venting gas out of the inside of the panel, comprising: atubulation tubing having, at a perimeter of one end, a flange with asubstantially flat end face for contact with the display panel; aring-shape adhesive member of a first glass frit material having a firstsoftening point fitted to the perimeter of the flange of the tubulationtubing for bonding the tubulation tubing to the display panel; and aring-shape auxiliary pressure member of a second, different glass fritmaterial having a second softening point higher than the first softeningpoint and a sealing temperature of the display panel greater than 500°C. fitted to the perimeter of the flange of the tubulation tubing so asto lie on an upper end face of the adhesive member.
 2. The assemblyaccording to claim 1, wherein the auxiliary pressure member has anon-oxidizable property.
 3. The assembly according to claim 1, whereinthe display panel is one of a plasma display panel, a plasma addressliquid crystal panel, a vacuum fluorescence display panel and a fieldemission display.
 4. The assembly according to claim 1, wherein thefirst softening point is less than about 400° C.
 5. The assemblyaccording to claim 1, wherein the first softening point is in a range ofabout 390° C. to about 410° C.
 6. The assembly according to claim 1,wherein the adhesive member contains at least one of PbO, SiO₂, Al₂O₃,B₂O₃ and LiO.
 7. The assembly according to claim 1, wherein the adhesivemember has a thermal expansion coefficient of 72.5+/−5×10−7/° C.
 8. Theassembly according to claim 1, wherein the adhesive member includes abinder resin selected from at least one of acrylic resin, methacrylicresin and cellulose resin.
 9. The assembly according to claim 1, whereinthe adhesive member has a substantially rectangular cross section. 10.The assembly according to claim 1, wherein the auxiliary pressure memberhas an expansion coefficient substantially similar to that of theadhesive member.
 11. The assembly according to claim 1, wherein theauxiliary pressure member contains at least one of Na₂O, Al₂O₃, B₂O₃ andSiO₂.
 12. The assembly according to claim 1, wherein the auxiliarypressure member is one of a glass containing Na₂O—B₂O₃ and a ceramic.13. The assembly according to claim 1, wherein the tubulation tubing hasa third softening point in a range of greater than 500° C. to about 700°C.
 14. The assembly according to claim 1, wherein the tubulation tubingis soda lime glass.
 15. A tubulation adhesion structure for connecting atubulation tubing to a vent hole of a display panel, comprising: atubulation tubing having, at one end, a flange with an end facecontacted with a periphery of the vent hole of the display panel; aring-shaped first glass frit member fitted to a perimeter of the flangeof the tubulation tubing so as to have the end face bonded to thedisplay panel; and a ring-shaped second glass member having a highersoftening point than that of the first glass frit member and fixed to anend face of the glass frit opposite from the display panel so as to keepthe end face of the glass frit from contact with any other member,wherein the second ring-shaped glass member has a softening pointgreater than 500° C., and higher than a sealing temperature of thedisplay panel.
 16. A tubulation adhesion structure of a display panelcomprising: a tubulation tubing connected to a vent hole formed in thedisplay panel, having a first end and a second, opposite end, wherein atthe first end there is provided an opening communicated with the venthole and a flange with a perimeter and a substantially flat end facecontacted with the display panel; a ring-shape glass frit arranged atthe perimeter of the flange, the glass frit being softened by heating;and a ring-shape auxiliary pressure member positioned at the perimeterof the flange between the glass frit and the second end, wherein theauxiliary pressure member is formed of a glass material having asoftening point greater than 500° C., and higher than a sealingtemperature of the display panel, wherein the flange is connected to thedisplay panel through the softening of the glass frit by the heating,and the auxiliary pressure member covers an end face of the glass fritopposite from the display panel, remains unsoftened.
 17. The structureaccording to claim 16, wherein the glass frit and the auxiliary memberhave substantially the same thermal expansion coefficient.
 18. Thestructure according to claim 16, wherein the auxiliary member has anon-oxidizable property.
 19. A tubulation assembly to be connected to avent hole of a planar surface of a display panel for venting gas out ofthe inside of the panel, comprising: a tubulation tubing having, at oneend, a flange with a substantially flat end face that contactscontinuously the planar surface of the display panel and a perimetersubstantially perpendicular to the flat end face; a ring-shape adhesivemember of a glass frit fitted to be bonded between the perimeter of theflange of the tubulation tubing and the planar surface of the displaypanel for bonding in an air-tight manner the tubulation tubing to thedisplay panel; and a ring-shape auxiliary pressure member positioned onan upper end face of the adhesive member, wherein the auxiliary pressuremember is formed of a glass material having a softening point greaterthan 500° C., wherein a thickness of each of the adhesive member and theauxiliary pressure member is less than a thickness of the flange in alongitudinal direction of the tabulation tubing, and wherein the totalthickness of the adhesive member and the auxiliary pressure member islarger than the thickness of the flange prior to bonding of the adhesivemember, but equal to the thickness of the flange after bonding.
 20. Theassembly according to claim 19, wherein the auxiliary pressure memberhas a non-oxidizable property.
 21. The assembly according to claim 19,wherein the display panel is one of a plasma display panel, a plasmaaddress liquid crystal panel, a vacuum fluorescence display panel and afield emission display.
 22. The assembly according to claim 19, whereinthe adhesive member contains at least one of PbO, SiO₂, Al₂O₃, B₂O₃ andLiO.
 23. The assembly according to claim 19, wherein the adhesive memberhas a thermal expansion coefficient of 72.5+/−5×10−7/° C.
 24. Theassembly according to claim 19, wherein the adhesive member includes abinder resin selected from at least one of acrylic resin, methacrylicresin and cellulose resin.
 25. The assembly according to claim 19,wherein the adhesive member has a substantially rectangular crosssection.
 26. The assembly according to claim 23, wherein the auxiliarypressure member has an expansion coefficient substantially similar tothat of the adhesive member.
 27. The assembly according to claim 19,wherein the auxiliary pressure member contains at least one of Na₂O,Al₂O₃, B₂O₃ and SiO₂.
 28. The assembly according to claim 19, whereinthe auxiliary pressure member is one of a glass containing Na₂O—B₂O₃ anda ceramic.
 29. The assembly according to claim 19, wherein thetubulation tubing has a softening point in a range of greater than 500°C. to about 700° C.
 30. The assembly according to claim 29, wherein thetubulation tubing is soda lime glass.
 31. The assembly according toclaim 19, wherein the adhesive member and the auxiliary pressure memberhave substantially the same thermal expansion coefficient.
 32. A plasmadisplay panel comprising: a front substrate; a back substrate having avent hole; a seating member for sealing the front substrate and the backsubstrate together; and a tubulation tubing connected to the vent hole,wherein the tubulation tubing has, at one end, a flange with an end facecontacted with a periphery of the vent hole of the display panel; aring-shaped first glass frit member fitted to a perimeter of the flangeof the tubulation tubing so as to have the end face bonded to thedisplay panel; and a ring-shaped second glass member having a highersoftening point than that of the first glass frit member and fixed to anend face of the glass frit opposite from the display panel so as to keepthe end face of the glass frit from contact with any other member,wherein the second ring-shaped glass member has a softening pointgreater than 500° C., and higher, than a sealing temperature of thedisplay panel.